Southern California -- this just in

The first major study of motorcycle crashes in nearly 30 years is underway in Los Angeles, as researchers attempt to pinpoint why resultant fatalities have soared over the last decade to constitute 14% of all roadway deaths, despite the fact that motorcycles account for less than 1% of vehicle miles traveled.

There are plenty of theories to explain the increase: The number of motorcycles on the road increased from 3.9 million in 1998 to 7.1 million in 2007; motorcycles are more powerful than they used to be; riders are older, now averaging 41 years of age; and many states have repealed their helmet laws.

But there are no clear answers.

The last in-depth investigation of motorcycle crashes in the U.S. — the Hurt study — was conducted through USC and released in 1981. Efforts to update that information have been stymied by funding issues.Earlier this month, a new study was greenlighted by the U.S. Department of Transportation, but it’s a scaled-down version of what was originally planned, and a leading industry-backed safety group says the sample size will be too small to properly resolve the questions.

The National Transportation Safety Board originally recommended that the study include a sample size of 900 to 1,200 crashes. The Hurt study examined 900 crashes. But researchers at Oklahoma State University, tapped to conduct the new study, said use of such a large sample would cost $10 million to $12 million, far exceeding the federal government’s $4.2-million estimate.

As of Oct. 1, the study was moving forward with a sample size of 300 crashes.

“The motorcycle crash rate for injuries and deaths has increased every year for the past 10 years, so it was critical to get this study underway,” said Cathy St. Denis, spokeswoman for the Federal Highway Administration. "It will be one of the most comprehensive studies to be done in years and will help prevent future crashes."

The $3.1-million study includes $2 million from the highway reauthorization bill, $500,000 from the National Highway Traffic and Safety Administration, $500,000 from individual states and $100,000 from the American Motorcyclist Assn.

The Motorcycle Safety Foundation, a nonprofit group that develops rider training courses used by most states and is funded by major manufacturers such as Honda and Harley-Davidson, had offered $2.8 million in 2007 for a study if it included a sample size of 900 crashes.

The group refused to contribute to the scaled-down study because it “will not provide adequate sampling to achieve appropriate statistical significance and may not provide new insights," the organization said in a statement Tuesday. “This limited study will likely lend only a minimal degree of validation to the major, already known contributing motorcycle crash factors.”

There are about 100,000 motorcycle crashes in the U.S. each year, 5,290 of which resulted in death in 2008, according to the National Highway Traffic Safety Administration. According to the Motorcycle Safety Foundation, which draws heavily on findings from the 1981 Hurt study, major crash factors include rider error, such as overbraking and running wide in a curve; and alcohol involvement.

So far, data from 53 crashes have been gathered as part of the study’s pilot, which kicked off in L.A. last December to test data collection procedures and which concluded earlier this year. That crash data will be included in the official study of 300 crashes, which is also taking place in Los Angeles.

Preliminary results from the study will be available in a year, according to Oklahoma State’s Alan Tree. Final results won’t be available until at least 2013.